Uninterruptible power supplies are very important in protecting valuable electronic appliances, communication systems and various other applications from sudden power failure or other problems related to power loss. For those places where sudden power failure problems are common, uninterruptible power supplies, such as a backup power supply, play a major role by providing continuous power supply.
To protect against reverse-connection and over-voltage conditions, high-voltage reverse-connection protection diodes, transient voltage suppressor (TVS) diodes or fuses are conventionally used. The replacements of diodes or fuses, however, are very inconvenient.